W126 Guide Rod & Front Bushing Replacement
 

Our extra car, Sybill the beater 300SDL, has always had a bad case of the clunkies. When braking, you can feel it banging away right underneath your feet and, even though you'd never know it at the steering wheel, looking at the upper ball joints, control arm bushings and guide rod ends tells the rest of the tale: this car had a hard life before arriving at Area 51.

I'll cover replacing the gude rod bushings, upper control arms and lower control arm bushings in this.

First get it up on stands and get the wheels off:

If you look closely, you can see the torn boot on the guide rod bushing.

Pull the spring...

This works best if you place a floor jack under the lower control arm and slightly raise the control arm. Then, remove the retaining nuts from from the upper end of the shock absorber. Next, compress the spring; when it is fully copmpressed, lower the jack and allow the control arm to move fully downwards. If, you placed the disks correctly in the spring, and were able to fully compress it, it should be loose in the spring supports. Carefully pry it out of the support and carefully release the pressure on the spring.

Next, remove the shock absorber. To remove the lower, inboard mounting bolt from the control arm, compress the shock and tip the upper part outboard as far as possible in the wheel well. This is the only way to get a socket on that inner bolt.

You might as well remove the spring support so that you can access the bolt that secures the front part of the guide rod to the lower control arm. And, remove the brake calipers and steering arm from the hub assembly too. Hang the calipers from the sway bar with a coat hanger.

Remove the suspension bearing bracket. First, you'll have to remove the three bolts that attach the transverse stiffener to the suspension bearing bracket then, you can remove the two large bolts that hold the assembly to the chassis.

This guide rod bushing was shot. So is the other side.

More will be added as I continue work on the control arms....

I've been "here"
 

its not poticulary hard, but its not easy ether. i replaced the whole front end all the controle arms, tie rods, break reaction rod bushings.. everying that could be changes got changed. its was very hard to drive afterward do to the alignment being so horrabley off. but once it was aligned it drove like a dream.

A long piece of string (to line toe against rear wheels) and a carpenters level for getting camber set gets you close enough to safely drive to alignment shop. I did that with my W116 when I rebuilt the entire front end.

I did the same, only using just a tape measure, when I rebuilt the front suspension on the 560 Got it real close too...I may have even posted my alignment numbers afterward, but can't recall.

whunter and I replaced the guide rods, ball joints, upper control arms and tie rods on my '85 SD last weekend.

We drove it into his garage Saturday evening and did the driver side and then did the passenger side the next morning.

It feels soooooooo much better now.

I am considering replacing shocks, guide rod buchings and upper control arms and everything seems fairly straight forward except...... how is it possible to remove the bolt that holds the upper control arm to the frame without removing all the "spagghetti" in front of the brake reservoir on the driver's side? I would need to have a 2 year old's hand to get the bolt out...or need surgical tools?

This is a 300sdl.

I know the bolt you're speaking of.;)

My hands are larger than just about anybody except Brandon and I managed to reach in there and pull the bolt out. Now, I have to tell you, getting it back in was absolutely a PITA. Can't remember exactly how I maneuvered it into position to get it started, but, I'm sure it was done with fingertips.

I've got some strong advice for you: Remove the main vacuum line from the brake booster, carefully disconnect the attached vacuum hoses, and get it out of that area. Otherwise you'll break the plastic tit for the vacuum shut off and then it's $40.00 at the dealer.:o

Thanks Brian,

I will look at the vaccum hose and see how to remove it. Maybe I can find a long skinny pair of pliers to help steer the bolt back in (first I have to get it out !)

Getting it out is easy. You drive it out from the forward side of the fender. It then falls down to the bottom of "no-man's land". Then you fish it out with a telescopic claw or a magnet.

Good stuff, my SDLs suspension is going to be rebuilt before the SD (L has a bad ball joint on driver side so it's higher on the list). This is of course after I throw on an updated vac pump. :o